HOW BIRDS AFFECT THE ORCHARD. 299 
soft-bodied insects like caterpillars and other larve, young grasshop- 
pers, and spiders. Stomach examination shows that they are fed on 
caterpillars or spiders almost exclusively during the first week of their 
existence, after which the diet is gradually changed and becomes more 
varied. 
BIRDS OF PREY. 
When fruit trees are young, and more especially when they are in 
the nursery rows, they are subject in winter to attacks from various 
species of mice and rabbits, which gnaw the bark from the trunks, 
completely girdling the trees, and thus ruining them. As a case in 
point, may be mentioned a single small nursery a few acres in extent in 
Jowa, in which more than 3,00 trees had been girdled by rabbits ina 
single winter—one of several instances of equal damage that occurred 
in the same town. Ina nursery of less than 5 acres, situated in Mary- 
land, only a few miles from Washington, 2,000 out of about 4,000 
apple trees were girdled and ruined by rabbits within two months. 
It is very significant that the nursery was near farm buildings where 
the wild enemies of the rabbits did not dare to come, while a newly set 
orchard at a distant part of the farm, and close by woods and thickets, 
was hardly touched. 
Field mice and other small rodents are represented in the United 
States by numerous species, all of which may do mischief to young 
treés in winter, and most of which are doing some mischief at all sea- 
sons. Rabbits, asa rule, are not so numerous, but their larger size 
and fondness for young fruit trees makes their destructiveness fully 
as great as that of the smaller rodents, and, in fact, much greater in 
some sections where they are particularly abundant. But there is a 
group of birds which seems to be especially adapted to prey on these 
harmful rodents and hold their numbers within reasonable bounds; 
although it often happens that through the shortsightedness of man 
_. this wise arrangement is disturbed. 
This group comprises the hawks and owls, of which about 73 
important species and subspecies are found in the United States. Dr. 
A. K. Fisher has investigated’ the diet of these birds, and has shown 
that the great bulk of their food consists of injurious rodents. After 
an examination of some 2,700 stomachs, only 6 of the 73 species and 
subspecies are classed as in the main harmful; the testimony of stom- 
ach examination is overwhelmingly in favor of the majority of the 
species. Mice, rats, rabbits, gophers, and ground squirrels constitute 
the chief food of most of the larger species, while many harmful 
insects are destroyed by the smaller ones. These birds at times feed 
on smaller insectivorous birds and poultry, but mice and other rodents 
are by far the commonest food of most species. 
1 Bulletin 3, Div. Ornith. and Mamm., Dept. Agr., 1893. 
